Servings: Makes 8 large or 12 medium buns
To make buns: Dissolve the yeast in the warm milk in a large bowl. Add sugar, margarine, salt, eggs and flour. Mix well. Knead the dough into a large ball, using your hands dusted lightly with flour. Put in a bowl, cover and let rise in a warm place about 1 hour or until the dough had doubled in size. Roll the dough out on a lightly floured surface, until it is approximately 21 inches long by 16 inches wide and 1/4-inch thick.
Preheat oven to 400°.
To make filling: Combine the brown sugar and cinnamon in a bowl.
Spread the softened margarine over the surface of the dough, then sprinkle the brown sugar and cinnamon evenly over the surface. Working carefully from the long edge, roll the dough down to the bottom edge. Cut the dough into 1 3/4-inch slices, and place in a lightly greased baking pan. Bake for 10 minutes or until light golden brown.
To make icing: While the rolls are baking, combine the icing and ingredients. Beat well with an electric mixer until fluffy. When the rolls are done, spread generously with icing.